Telephonic transmitter



J. E. WATSON. Tel-ephonic-Trans mitter.

No. 226,376. Patented April 6,1880.

INVENTOR WITNESSES ATTORNEY N; PEER-5, FHDTO-LITHOGRAPHER. WASHINGTON. D. O.

UNITED STATES PATENT OFFICE.

JOHN E. WATSON, OF LOUISVILLE, KENTUCKY.

TELEPHONIC TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 226,376, dated April 6, 1880.

Application filed August 21, 1879.

To all whom it may concern:

Be it known that 1, JOHN E. WATSON, of Louisville, in the county of Jefferson and State of Kentucky, have invented a new and valuable Improvement in Telephonic Transmitters or Bheostats; and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings, making a part of this specification, and to the letters and figures of reference marked thereon.

Figure l of the drawings is a representation of aplan view of the transmitter with the mouthpiece removed and the diaphragm broken away to show the rings, the disk, and its sprin g-arms; and Fig. 2 is a central section of the transmitter.

This invention has relation to improvements in telephonic transmitters; and the nature of the invention consists in a soft elastic rubber case or tube, of any suitable compressible nonelectric conducting material, for the reception of a filling of carbon-powder, an exterior caseholder receiving said case, also made of an electric non-conductor, and a follower or plug in the end of the case-holder bearing against the case and adjustable to place the filling under compression.

It also consists in the non-electric conductor, elastic case, and its hard exterior non-electricconductor holder, in combination with an adjustable com pressing-plug fitting in the holder and bearing against the case, a carbon filling in finely-divided form in said case, a metallic disk closing the other end of the case, and having spring-arms bearing against the sounddiaphragm, a mouth-piece, binding-posts, and wire connections from the metallic diaphragm to the binding-posts.

It also consists of a soft elastic rubber tube or case, of any suitable con-conducting electric material, combined with a hard-rubber ring or tube, of any non-conductor of electricity, closely encircling and supporting the same, and containing an electric conductor in afinely-divided condition, as will be hereinafter more fully described.

In the annexed drawings, the letter A designates an elastic ring, made of soft rubber or other elastic material not being a conductor of electric currents, inclosed within a second ring, 0, made of hard rubber or other hard nonconductor of electricity, and inserted into a circular block, B. Into the exterior face of this block is recessed a metallic plate, I), having extended through it an adj usting-screw, S, the end of which bears against a metallic plug, 0, fitting loosely in the end of tube 0 and hearing against the end of the elastic ring A. This plug closes one end of this ring A, the other end whereof is covered with a metallic disk, d, having the projecting spring-arms e, the free ends of which bear against a thin metallic diaphragm, D, inclosed between the block B and the mouth-piece E. The faces of the block B and mouth-piece E contiguous to the diaphragm D are hollowed out or concaved to form sounding-chambers, and the inner faces of the plug and disk may be covered with platinum to prevent oxidation.

Within the case A, between the plug and disk, is a small chamber, designed to contain an electrical conducting material in a finelydivided condition. I preferably use a composition made of gas-carbon pulverized and a small percentage of brass filings.

i indicates recesses formed in the concave inner face of the block, in which are inserted metallic washers i, through which extend the screws j j, that secure the binding-posts I J to the block. The screw j is connected to the diaphragm D by a wire, 70, and its binding-post I is thus brought into electrical communication with the said diaphragm, and screw 9" is pro vided with a wire. leading to plate 1). Thus through this plate. the adjusting-screw S, the plug c,the electric conductor in tube A, and the disk d, having the arms e, the post J is elec-- between said disk and the brass plug is had,

thereby giving very loud articulation without affecting its distinctness, and yet of such delicate sensitiveness as to catch the faintest whisper.

What I claim as new, and desire to secure by Letters Patent, is

1. In a transmitter, the combination, with the block B, of a hard-rubber ring, 0, recessed into the same, a compressible interior rubber ring, A, inside of ring 0, and an. adjustable plug fitting in ring 0 and bearing against ring A, substantially as specified.

2. The soft elastic rubber tube or case, of any suitable non-conducting electric material, combined with a hardrubber ring or tube, of any non-conductor of electricity, closely encircling and supporting the same, and containing an electric conductor in a finely-difided condition, substantially as specified.

3. The elastic case A, bein a non-conductor of electricity, and the hard non-electric conducting-case 0, combined with the adjustable plug" 0, a carbon filling in case A, a metallic disk, (1, closing the other end of said case, and having the spring-arms e, the metallic diaphragm D, the mouth-piece E, binding-post I, wire k, connecting said diaphragm and post,

plate 0, adjusting-screw S, binding-post J, and 

